Docsis-moca coupled line directional coupler

ABSTRACT

A Docsis-MoCA coupled line directional coupler includes an input port, an output port, a coupled port, and a termination port. A first track connects the input port to the output port and a second track, which may be substantially parallel to the first track, connects the termination port to the coupled port. The first track and the second track are configured to form a variable coupling length so as to control, for instance, an isolation level between the output port and the coupled port to be less than a predetermined isolation level in a MoCA frequency band.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application62/969,554, which was filed on Feb. 3, 2020, and is incorporated hereinby reference in its entirety.

BACKGROUND

Data Over Cable Service Interface Specification (DOCSIS) is aninternational telecommunications standard that permits the addition ofhigh-bandwidth data transfer to an existing cable television (CATV)system. DOCSIS is used by many cable television operators to provideInternet access over their existing hybrid fiber-coaxial (HFC)infrastructure. The Multimedia over Coax Alliance (MoCA) is aninternational standards consortium that publishes specifications fornetworking over coaxial cable. DOCSIS may be useful for providingnetwork content via home cable TV subscriber devices (e.g., digitalvideo recorders (DVRs), set-top boxes, digital television tuners, etc.).Also, MoCA may be useful to allow network devices and/or home cable TVsubscriber devices to communicate with each other over a wired coaxialconnection.

MoCA filtering is a technique used to prevent communications betweendevices in a home network from exiting the home network and reaching theCATV network or external network. Such filtering is often used topreserve the privacy of the communications occurring within the homenetwork and more specifically, to prevent communications, intended onlyfor devices within the home network, from leaving the home network andbeing observable from outside the home network.

A challenge in using Docsis to provide cable TV and Ethernet signals toand from the home and MoCA signals for networking of data within thehome is providing sufficient isolation between the cable signals and theInternet or other signals and controlling insertion loss and return losswithin the home. An additional challenge is preventing noise funnelingof interference signals in the Docsis band escaping from the home wherethe aggregate sum noise from multiple homes could degrade the CATVsignals in the network. Many in home cable architectures now useproducts that help to improve isolation between CATV access networksignals and In-home network signals while also suppressing or minimizingnoise ingress.

SUMMARY

A Docsis-MoCA coupled line directional coupler includes an input port,an output port, a coupled port and a termination port. A first trackconnects the input port to the output port and a second tracksubstantially parallel to the first track connects the termination portto the coupled port. A coupling length between the first track and thesecond track is set so as to control an isolation level between theoutput port and the coupled port to be less than a predeterminedisolation level in a MoCA frequency band.

In some embodiments, a resistor is connected between a ground and thesecond track, and a connection position of the resistor to the secondtrack along a length of the second track is set to control the couplinglength between the first track and the second track.

In some embodiments, a coupling length between the first track and thesecond track is set so as to control an isolation level between theinput port and the coupled port being set to be less than a secondpredetermined isolation level at a Docsis frequency band and anisolation level between the input port and the coupled port being set beless than a third predetermined isolation level at the MoCA frequencyband.

In some embodiments, a coupling length between the first track and thesecond track is set so as to control an insertion loss level between theinput port and output port of less than a predetermined insertion losslevel at a predetermined frequency.

In some embodiments, a coupling length between the first track and thesecond track is set so as to control one or more of: an isolation levelbetween the output port and the coupled port to be less than apredetermined isolation level in a MoCA frequency band, an isolationlevel between the input port and the coupled port being set to be lessthan a second predetermined isolation level at a Docsis frequency bandand an isolation level between the input port and the coupled port beingset be less than a third predetermined isolation level at the MoCAfrequency band, and an insertion loss level between the input port andoutput port of less than a predetermined insertion loss level at apredetermined frequency.

In some embodiments, the coupling length between the first track and thesecond track may be set to provide a more uniform isolation levelbetween the output port and the coupled port, and/or between the inputport and the coupled port as well as an improved insertion loss betweenthe input port and the output port.

It will be appreciated that this summary is intended merely to introducesome aspects of the present methods, systems, and media, which are morefully described and/or claimed below. Accordingly, this summary is notintended to be limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the presentteachings and together with the description, serve to explain theprinciples of the present teachings. In the figures:

FIG. 1 illustrates an example Docsis-MoCA coupled line directionalcoupler in accordance with aspects of the present disclosure.

FIG. 2 illustrates an example adjustable Docsis-MoCA coupled linedirectional coupler in accordance with aspects of the presentdisclosure.

FIG. 3 illustrates a top view of an example PCB design for a Docsis-MoCAcoupled line directional coupler in accordance with aspects of thepresent disclosure.

FIG. 4 illustrates an example adjustable Docsis-MoCA coupled linedirectional coupler implemented in a test circuit.

FIG. 5 illustrates a graph of the input to hybrid port insertion lossfor the Docsis-MoCA coupled line directional coupler, in accordance withaspects of the present disclosure.

FIG. 6 illustrates a graph of the hybrid port to MoCA-only portisolation for the Docsis-MoCA coupled line directional coupler, inaccordance with aspects of the present disclosure.

FIG. 7 illustrates a graph of the input port to MoCA-only port isolationfor the Docsis-MoCA coupled line directional coupler, in accordance withaspects of the present disclosure.

DETAILED DESCRIPTION

Aspects of the present disclosure may include a Docsis-MoCA coupled linedirectional coupler that improves the performance of hybrid and MoCAonly communications by improving insertion loss and isolation betweenthe ports. Further, the performance of the Docsis-MoCA coupled linedirectional coupler may be adjusted or set when the Docsis-MoCA coupledline directional coupler is manufactured, as further explained herein.

Additionally, in some embodiments, a coupling length of lines or tracksin the Docsis-MoCA coupled line directional coupler may be adjustable byadjusting a connecting position of a resistor to one of the tracks,thereby adjusting the isolation, transition frequency and insertionloss. The coupling length may be defined by a portion of the first trackand the second track that may be, but is not limited to, being inparallel with each other and through which the signal is activelycoupled.

As described herein, the Docsis-MoCA coupled line directional couplermay include a splitter design with tuned MoCA frequency band (e.g.,1125-1675 MHz) performance and may be constructed and/or optimized usingstandard PCB materials. In some embodiments, these materials may includea PCB with FR4 (flame retardant woven glass reinforced epoxy resin), aPCB thicknesses of about 30-62 mil and performance in the Docsis & MoCAfrequency bands (e.g. 5-1002 MHz & 1125-1675 MHz). The Docsis-MoCAcoupled line directional coupler described herein may have a microstripsymmetrical coupled line design that improves the thermal behavior,insertion loss and directional isolation in the Docsis & MoCA frequencybands (e.g. 5-1002 MHz & 1125-1675 MHz) relative to the thermalbehavior, insertion loss and directional isolation of traditionaltoroidal couplers.

Referencing a single stage Docsis-MoCA coupled line directional couplerwith microstrip symmetrical coupled line design, specific designcharacteristics may be optimized in the Docsis & MoCA frequency bands(e.g. 5-1002 MHz for Docsis and 1125-1675 MHz for MoCA) throughsimulation and prototype iterations. Example design characteristics thatmay be optimized may include stage quantity, microstrip track widths,coupling lengths, clearances, resistance values, resistor location,straight line, dual line and folded line layouts such that devices aresuitable for Docsis-MoCA dual network applications within the examplefrequency range of 5-1002 MHz and 1125-1675 MHz.

As described herein, in some embodiments, the Docsis-MoCA coupled linedirectional coupler may include a single stage microstrip symmetricalcoupled line design. In some embodiments, the directional coupler may beformed on a PCB. In some embodiments, the Docsis-MoCA coupled linedirectional coupler includes: an input port, an output port, a coupledport and a termination port, a first track connecting the input port tothe output port, and a second track substantially parallel to the firsttrack connecting the termination port to the coupled port. A couplinglength between the first track and the second track may be set toprovide the Docsis-MoCA coupled line directional coupler with anisolation level between the output port and the coupled port that can becontrolled. In some embodiments, the isolation level between the outputport and the coupled port may be controlled (by setting the couplinglength) to be less than a first predetermined isolation level, such asless than about 8 dB at a MoCA frequency band, such as 1125-1675 MHz.

In some embodiments, the first track and the second track are configuredto form a coupling length based on a resistor connection positionrelative to or along a length of the second track. In some embodimentsthe first track and the second track may be configured to form differentcoupling lengths. For example, the first track and the second track maybe configured to form a first coupling length, a second coupling length,a third coupling length, etc, by the use of different connectionpositions of the resistor along the second track. The different couplinglengths can provide different levels of isolation between the ports asdescribed herein, as well as different levels of insertion loss.

The coupling length may also be set to provide the Docsis-MoCA coupledline directional coupler with one or more of: 1) an isolation levelbetween the input port and the coupled port of less than a secondpredetermined isolation level, such as less than about 35 dB at a Docsisfrequency band, such as about 5-1002 MHz, and less than a thirdpredetermined isolation level, such as less than about 25 dB at a MoCAfrequency band, such as 1125-1675 MHz in a standalone configuration; and2) an insertion loss between the input port and the output port of lessthan a predetermined insertion loss level, such as about 1.5 dB at about1200 MHz. In some embodiments, other predetermined isolation levels,insertion loss levels and frequency bands may be used. For example, anisolation level between the input port and the coupled port of less thanabout 40 dB at a Docsis frequency band may be used, and an isolationlevel between the input port and the coupled port of less than about 30dB at a MoCA frequency band may be used. The coupling length can be setto provide other isolation levels as needed.

In some embodiments, the coupling length between the first track and thesecond track may be set to provide a more uniform isolation levelbetween the output port and the coupled port, and/or between the inputport and the coupled port, as further explained herein.

In some embodiments, in addition to the coupling length, a gap widthbetween the first track and the second track and/or a width of the firsttrack and a width of the second track may be set to control a value ofone or more of the isolation between the output port and the coupledport, the insertion loss between the input port and the output port, andan isolation between the output port and the and coupled port. In someembodiments, the values of the gap width, the track width and otherelement details may be optimized for the Docsis and MoCA bandwidths.

In some embodiments, the track width may be about 14±1.5 mil; the gapbetween the first track and the second track may be about 5.5±1 mil; aclearance to ground may be 25 mil; the PCB thickness may be about 39mil; and the coupling length of the first track and the second track maybe about 1200 mil. A resistor may be connected between the second trackand ground. The connection point of the resistor to the second track maybe used to adjust the coupling length. In some embodiments, the resistormay have a resistance of about 75Ω.

In some embodiments, the values of the gap width, the track width, theclearance to ground, the PCB thickness and the value of the resistor maybe set to nominal values (such as given in the preceding paragraph), andthen the coupling length between the first track and the second trackmay be set to provide desired levels for one or more of: 1) a level ofisolation between the input port and the coupled port; 2) a level ofisolation between the output port and the coupled port; 3) a level ofinsertion loss between the input port and the output port; 4) auniformity of the isolation between the input port and the coupled portacross one or more frequency band (such as the herein described Docsisand MoCA frequency bands); and 5) a uniformity of the isolation betweenthe output port and the coupled port across one or more frequency band(such as the herein described Docsis and MoCA frequency bands).

In some embodiments the Docsis-MoCA coupled line directional coupler maybe modified such that the coupled lines may be folded to maintain designperformance while using less space. In some embodiments, the Docsis-MoCAcoupled line directional coupler may be modified by adjusting aconnection position of the resistor along a length of the second track,effectively lengthening or shortening the coupling length of the firstand second tracks. In some embodiments, the Docsis-MoCA coupled linedirectional coupler may be modified such that the performance issustained for different PCB thicknesses and materials. While certainexample characteristics, measurements, parameters, and specificationsare described above, it is noted that in practice, variations arepossible and aspects of the present disclosure are not limited to thosecharacteristics, measurements, parameters, and specifications describedherein.

Reference will now be made in detail to embodiments, examples of whichare illustrated in the accompanying drawings and figures. In thefollowing detailed description, numerous specific details are set forthin order to provide a thorough understanding of the invention. However,it will be apparent to one of ordinary skill in the art that theinvention may be practiced without these specific details. In otherinstances, well-known methods, procedures, components, circuits, andnetworks have not been described in detail so as not to unnecessarilyobscure aspects of the embodiments.

It will also be understood that, although the terms first, second, etc.may be used herein to describe various elements, these elements shouldnot be limited by these terms. These terms are only used to distinguishone element from another. For example, a first object or step could betermed a second object or step, and, similarly, a second object or stepcould be termed a first object or step, without departing from the scopeof the present disclosure. The first object or step, and the secondobject or step, are both, objects or steps, respectively, but they arenot to be considered the same object or step.

The terminology used in the description herein is for the purpose ofdescribing particular embodiments and is not intended to be limiting. Asused in this description and the appended claims, the singular forms“a,” “an” and “the” are intended to include the plural forms as well,unless the context clearly indicates otherwise. It will also beunderstood that the term “and/or” as used herein refers to andencompasses any possible combinations of one or more of the associatedlisted items. It will be further understood that the terms “includes,”“including,” “comprises” and/or “comprising,” when used in thisspecification, specify the presence of stated features, integers, steps,operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof. Further, asused herein, the term “if” may be construed to mean “when” or “upon” or“in response to determining” or “in response to detecting,” depending onthe context.

Attention is now directed to processing procedures, methods, techniques,and workflows that are in accordance with some embodiments. Someoperations in the processing procedures, methods, techniques, andworkflows disclosed herein may be combined and/or the order of someoperations may be changed.

FIG. 1 illustrates an example Docsis-MoCA coupled line directionalcoupler 100 in accordance with aspects of the present disclosure. TheDocsis-MoCA coupled line directional coupler 100 of FIG. 1 may includean input port 102, an output port 104, a termination port 106 and acoupled port 108. A resistor 110 may be connected between thetermination port 106 and a ground 112. The input port 102 is connectedto the output port 104 by a first track 114 and the termination port 106is connected to the coupled port by a second track 116.

The Docsis-MoCA coupled line directional coupler 100 may be configuredto receive a signal, such as an incoming or “downstream” cable TVsignal, at the input port 102 and output the cable TV signal at theoutput port 104. Additionally, the coupled port is configured to coupleMoCA signals to the Output Hybrid Port while isolating CATV Signals andMoCA signals from the input port. In some embodiments, the output port104 may be a hybrid port that outputs both the cable TV signal and aMoCA data signal (see FIG. 7).

The Docsis-MoCA coupled line directional coupler 100 is configured toprovide isolation between the output port 104 and the coupled port 108(and between the output CATV signal and the MoCA signal output at thecoupled port 108). As further described herein, the isolation betweenthe output port 104 and the coupled port 108 is set to a desiredisolation level by setting a coupling length between the first track 114and the second track 116. In one example, the isolation between theoutput port 104 and the coupled port 108 may be set to 8 dB (althoughdifferent levels of isolation may be used) at a MoCA frequency, such asat about 1125-1675 MHz.

The isolation level between the output port 104 and the coupled port 108may be set by adjusting a coupling length between the first track 114and the second track 116. For example, the coupling length may be set byconnecting the resistor 110 to the second track 116 at one of variouspositions along a length of the second track 116. The coupling lengthcan be lengthened or shortened in this manner. In some embodiments, theDocsis-MoCA coupled line directional coupler 102 may be connected totest equipment capable of measuring the isolation level, insertion loss,etc., and the resistor 110 can be moved along a length of the secondtrack 116 to change the coupling length until the desired isolationlevel is achieved.

Setting the coupling length between the first track 114 and the secondtrack 116 may also be used to set an isolation between the input port102 and coupled port 108. In some embodiments, the isolation between theinput port 102 and coupled port 108 may be set to less than about 35 dBat a DOCSIS frequency, such as about 5-1002 MHz and less than about 25dB at a MoCA frequency, such as about 1125-1675 MHz, for example,although other isolation levels could be set.

Setting the coupling length between the first track 114 and the secondtrack 116 may also be used to set an insertion loss between the inputport 102 and output port 104. In some embodiments, the insertion lossmay be set to less than about 1.5 dB at about 1200 MHz, for example.

In some embodiments, in addition to the coupling length between thefirst track 114 and the second track 116, other factors may affect theherein-described isolation values and insertion loss. These otherfactors may include a resistance value of resistor 110, a track width ofthe first and second tracks 114, 116, a gap between the first track 114and the second track 116, a thickness of the printed circuit board onwhich the Docsis-MoCA coupled line directional coupler 102 is formed, adielectric constant of the printed circuit board, and a loss tangent ofthe printed circuit board. However, if these other factors are fixed,the isolation levels and insertion loss may be adjusted based on achange in the coupling length.

In some embodiments, the Docsis-MoCA coupled line directional coupler102 may be configured with the resistor 110 having a value of 75 ohms,the track width of the first track 114 and the second track 116 may beabout 14 mil±1.5 mil, the gap between the tracks may be 5.5 mil±1 mil,the clearance to ground may be 25 mil. Other values for these elementsmay be used, but these values have been found to produce useful levelsof isolation and insertion loss when used with a starting value of thecoupling length of the first track 114 and the second track 116 of about1200 mil, as further explained herein.

FIG. 2 illustrates an example Docsis-MoCA coupled line directionalcoupler 118 in accordance with aspects of the present disclosure. TheDocsis-MoCA coupled line directional coupler 118 is shown with multipleresistor positions (e.g., three resistor positions) 120, 122, 124, butin practice one resistor may be moved to different positions 126, 128and 130 along the length of second track 116. In some embodiments, theDocsis-MoCA coupled line directional coupler 118 could include multipleresistor positions that are at different connection points along thelength of the second track 116, where one of the resistors areselectively connectable between the ground 112 and the second track 116to change the coupling length of the tracks 114, 116.

FIG. 3 illustrates a top view of an example printed circuit board (PCB)300 for a Docsis-MoCA coupled line directional coupler in accordancewith aspects of the present disclosure. The Docsis-MoCA coupled linedirectional coupler of FIG. 3 may have the coupling length between thefirst track 114 and the second track 116 set to provide the isolationand/or insertion loss described above. The coupling length is defined bythe portion of the first track and the second track that are paralleland through which the signals are actively coupled. The position of theresistor along the second track can thus be used to adjust the couplinglength.

FIG. 4 illustrates an example adjustable Docsis-MoCA coupled linedirectional coupler 401 implemented in a test circuit 400. As shown inFIG. 4, the adjustable Docsis-MoCA coupled line directional coupler 401may include an input port 402 that may be connected to an input source(e.g., a CATV input source) to receive input signals (e.g., inputsignals from a CATV provider or network, such as television signals forbroadcasting television content). The Docsis-MoCA coupled linedirectional coupler 401 may be configured to connect to home subscriberdevices (e.g., set-top boxes, television tuners, etc.) via an outputport 404 to provide the home subscriber devices with connectivity to theCATV network and receive signals provided by the CATV network for thehome subscriber devices to present television content. The output port404 may also provide MoCA connectivity in which the home subscriberdevices may communicate with each other via the MoCA protocol within thein-home network. The Docsis-MoCA coupled line directional coupler 401may also include a coupled port 408 to provide MoCA only access in whichthe MoCA devices may communicate with each other while isolating themfrom the input port or the CATV network (e.g., to preserve privacy ofthe communications within the home network). A resistor 410 may beconnected between ground 412 and a second track 416. A first track 414is connected between the input port 402 and the output port 404.

Although resistors R1-R4 are shown in FIG. 4, the Docsis-MoCA coupledline directional coupler 401 may be configured with just one resistorconnectable at different positions along a length of the second track416, or may be configured with a plurality of resistors selectivelyconnectable at different positions along a length of the second track416 for adjusting the coupling length.

The test circuit 400 is configured to measure the isolation andinsertion loss between the ports. The connection position of theresistor 410 to the track (by connecting the resistor 410 at differentconnection positions along the track) can then be adjusted to providedesired values for the isolation and insertion loss between the variousports, as described herein. The test circuit may be used to determinethe nominal directional coupler design parameters and resistor placementto optimize isolation and insertion loss performance for various loadsattached to the various ports such as splitters and cables. Thereactance of these loads are what interact with the performancecharacteristics of the directional coupler.

As described herein, the Docsis-MoCA coupled line directional coupler401, in accordance with aspects of the present disclosure, includes animproved design that improves the performance of hybrid and MoCA onlycommunications by improving insertion loss and isolation levels anduniformity as compared to conventional devices.

FIG. 5 illustrates a graph of the input to hybrid port (or output port)insertion loss for the Docsis-MoCA coupled line directional coupler 100,401, at various coupling lengths such as 1050 mil to 1200 mil inaccordance with aspects of the present disclosure. As can be seen inFIG. 5, the insertion loss is less than about 1.5 dB starting at 1200mil.

FIG. 6 illustrates a graph of the hybrid port (or output port) toMoCA-only port (or coupled port) isolation for different couplinglengths (represented as R1-R4) for the Docsis-MoCA coupled linedirectional coupler 100, 401, in accordance with aspects of the presentdisclosure. As can be seen in FIG. 6, the isolation is less than about 8dB at about the MoCA frequency band of 1125 MHz to 1675 MHz fordifferent R values. The coupled response between the output port (hybridport) and the coupled port (MoCA only port) can be flattened byselecting the proper resistive position or track coupling length inconjunction with the series capacitance of the coupled port load. InFIG. 6, R2 is the flattest of the coupling lengths shown, and thusprovides the highest level of uniformity of the isolation level acrossthe MoCA frequency band.

FIG. 7 illustrates a graph of the input port to MoCA-only port (coupledport) isolation for the Docsis-MoCA coupled line directional coupler100, 401, in accordance with aspects of the present disclosure. As canbe seen in FIG. 7, the isolation is less than about 25 dB at the MoCAfrequency band of about 1125-1675 MHz and less than about 35 dB at theDocsis frequency band of about 5 MHz to about 1002 MHz. In someembodiments, other isolation levels may be used. For example, anisolation level between the input port and the coupled port of less thanabout 40 dB at a Docsis frequency band may be used, and an isolationlevel between the input port and the coupled port of less than about 30dB at a MoCA frequency band may be used. The coupling length can be setto provide other isolation levels as needed.

The coupled response between the input port and the coupled port can beskewed by selecting the proper resistive position or coupling length inconjunction with the series capacitance of the coupled port load (traceor component value). An objective is to provide a high isolation acrossthe Docsis frequency band. In FIG. 7, R2 has the best frequency responsein the Docsis frequency band. Additionally, R2 provides the mostuniformity of the isolation level across the Docsis frequency band.

As shown in FIGS. 5-7, the Docsis-MoCA coupled line directional coupler100, 401 may produce excellent results for the isolation levels andinsertion loss in accordance with aspects of the present disclosure.Further, the results for the insertion loss and isolation levels can beadjusted by setting the coupling length between the first and secondtracks of the Docsis-MoCA coupled line directional coupler as describedherein. While other factors can affect the isolation levels andinsertion loss, such as the track widths, the gap width between thetracks, the thickness of the PCB, a resistance value of the resistorconnecting the second track to ground, etc., these other factors can beset to nominal values, such as those described herein, and then thecoupling length can be set (by setting the connection position of theresistor along the length of the second track) to provide theDocsis-MoCA coupled line directional coupler with desired levels ofisolation between the output port and the coupled port and between theinput port and the output port at the Docsis and MoCA frequency bands.In addition, the coupling length can be set to provide increaseduniformity of the isolation levels across the Docsis and MoCA frequencybands.

The foregoing description, for purpose of explanation, has beendescribed with reference to specific embodiments. However, theillustrative discussions above are not intended to be exhaustive orlimiting to the precise forms disclosed. Many modifications andvariations are possible in view of the above teachings. Moreover, theorder in which the elements of the methods described herein areillustrate and described may be re-arranged, and/or two or more elementsmay occur simultaneously. The embodiments were chosen and described inorder to best explain the principals of the disclosure and its practicalapplications, to thereby enable others skilled in the art to bestutilize the disclosed embodiments and various embodiments with variousmodifications as are suited to the particular use contemplated.

What is claimed is:
 1. A coupler for a Docsis-MoCA coupled linecomprising: an input port, an output port, a coupled port and atermination port; a first track configured to connect the input port andthe output port; a second track configured to connect the first trackthe termination port to the coupled port; wherein the second track isconfigured to be substantially parallel to the first track; wherein thecoupler comprises a directional coupler for a Docsis-MoCA coupled line;wherein the first track and the second track are configured to form acoupling length based on a resistor connection position relative to thesecond track; wherein the first track and the second track areconfigured to form a first coupling length, where the resistorconnection position is spaced along the second track at a firstconnection position, and a second coupling length, where the resistorposition is spaced along the second track at a second connectionposition that is different from the first connection position; wherein acoupling length between the first track and the second track isconfigured to provide an isolation level between the output port and thecoupled port that is less than a first predetermined isolation level ata MoCA frequency band; and wherein the coupling length between the firsttrack and the second track is configured so that an isolation levelbetween the input port and the coupled port is less than a secondpredetermined isolation level at a Docsis frequency band; wherein thecoupling length between the first track and the second track isconfigured so that the isolation level between the input port and thecoupled port is less than a third predetermined isolation level at theMoCA frequency band; wherein the coupling length between the first trackand the second track is configured so that the insertion loss levelbetween the input port and output port is less than a predeterminedinsertion loss level at a predetermined frequency; wherein the firstpredetermined isolation level is about 8 dB and the MoCA frequency bandis about 1125-1675 MHz; wherein the second predetermined isolation levelis about 35 dB; wherein the Docsis frequency band is about 5 to 1002MHz; and wherein the third predetermined isolation level is about 25 dB.2. The coupler of claim 1, wherein the predetermined insertion losslevel is about 1.5 dB and the predetermined frequency is about 1200 MHz.3. The coupler of claim 1, wherein the resistor is configured to beconnected between a ground and the second track, wherein the couplinglength is configured to be selectively adjusted by allowing theconnection position of the resistor to the second track to be movedalong a length of the second track.
 4. The Docsis-MoCA coupled linedirectional coupler of claim 1, wherein a track width of the first trackand the second track is about 14±1.5 mil, and a gap between first trackand the second track is about 5.5±1 mil.
 5. A coupler for a Docsis-MoCAcoupled line comprising: an input port, an output port, a coupled port,and a termination port; a first track configured to connect the inputport and the output port; a second track configured to connect thetermination port to the coupled port; wherein a coupling length betweenthe first track and the second track is configured to provide anisolation level between the output port and the coupled port being thatis less than a first predetermined isolation level at a MoCA frequencyband during operation of the coupler; wherein the coupling lengthbetween the first track and the second track is based on a resistorposition relative to the second track; wherein the coupling lengthbetween the first track and the second track is configured to provide anisolation level between the input port and the coupled port that is lessthan a second predetermined isolation level at a Docsis frequency bandduring operation of the coupler; and wherein the coupling length betweenthe first track and the second track is configured to provide anisolation level between the input port and the coupled port that is lessthan a third predetermined isolation level at the MoCA frequency bandduring operation of the coupler.
 6. The coupler of claim 5, wherein thecoupler comprises a directional coupler, and wherein the second track isconfigured to be substantially parallel to the first track.
 7. Thecoupler of claim 5, wherein the first track and the second track areconfigured to form a first coupling length, where the resistor positionis connected along the second track at a first position, and a secondcoupling length, where the resistor is connected along the second trackat a second position that is different from the first position.
 8. Thecoupler of claim 7, wherein when the first track, the second track andthe resistor connection position form the first coupling length, theisolation level between the output port and the coupled port is lessthan the first predetermined isolation level at a MoCA frequency bandduring operation of the coupler.
 9. The coupler of claim 7, wherein whenthe first track, the second track and the resistor connection positionform the second coupling length, the isolation level between the outputport and the coupled port is less than the second predeterminedisolation level at a MoCA frequency band during operation of thecoupler.
 10. The coupler of claim 5, wherein the first predeterminedisolation level between the output port and the coupled port is about 8dB, wherein the MoCA frequency band is about 1125-1675 MHz, wherein thesecond predetermined isolation level between the input port and thecoupled port is about 35 dB, wherein the third predetermined isolationlevel is about 25 dB, wherein the Docsis frequency band is about 5 to1002 MHz, and wherein the insertion loss between the input port andoutput port is less than about 1.5 dB at about 1200 MHz.
 11. The couplerof claim 5, further comprising a resistor connected between a ground andthe second track, wherein the coupling length is configured to beadjusted by changing a resistor connection position along a length ofthe second track.
 12. The coupler of claim 7, wherein the resistor has aresistance of about 75 ohms, wherein a track width of the first trackand the second track is about 14±1.5 mil, wherein a gap between firsttrack and the second track is about5.5±1 mil, wherein the couplercomprises a single stage microstrip symmetrical coupled line directionalcoupler on an FR4 PCB, and wherein the PCB comprises a thickness of 39mil, a dielectric constant of about 4.4, and a loss tangent of 0.015.13. A coupler comprising: an input port, an output port, a coupled port,and a termination port; a first track configured to connect the inputport to the output port; a second track configured to connect thetermination port to the coupled port wherein the first track and thesecond track are configured to form a variable resistor coupling lengthbetween the first track and the second track so as to control anisolation level between the output port and the coupled port to be lessthan a predetermined isolation level in a MoCA frequency band duringoperation of the coupler; and wherein the variable resistor couplinglength is based on a position of a resistor relative to the second tracksuch that when the resistor is located at a first position relative tothe track, the isolation level between the output port and the coupledport is less than the predetermined isolation level in a MoCA frequencyband during operation of the coupler, and such that when the resistor islocated at a second position relative to the second track that isdifferent from the first position, the isolation level between theoutput port and the coupled port is greater than the predeterminedisolation level in the MoCA frequency band during operation of thecoupler.
 14. The coupler of claim 13, wherein the coupler comprises aDocsis-MoCa coupled line directional coupler.
 15. The coupler of claim13, wherein the second track is configured to be substantially parallelto the first track.
 16. The coupler of claim 13, wherein thepredetermined isolation level between the output port and the coupledport is about 8 dB, and wherein the MoCA frequency band is about1125-1675 MHz.
 17. The coupler of claim 13, wherein the resistor isconfigured to be connected between a ground and the second track, andwherein the variable resistor coupling length is configured to beadjusted to allow the resistor to be connected to the second track atdifferent positions along a length of the second track.
 18. The couplerof claim 13, wherein the insertion loss between the input port and theoutput port is less than about 1.5 dB at about 1125-1675 MHz, whereinthe isolation level between the input port and the coupled port is lessthan about 35 dB at about 5-1002 MHz, and wherein the isolation levelbetween the input port and the coupled port is less than approximately25 dB at about 1125-1675 MHz.
 19. The coupler of claim 13, wherein a gapwidth between the first track and the second track and a width of thefirst track and a width of the second track are configured to controlthe isolation between the output port and the coupled port.
 20. Thecoupler of claim 19, wherein the gap width is about 5.5 mil±1 mil, thewidth of the first track and the width of the second track about 14±1.5mil, and the resistor has a resistance of about 75 ohms.